Thumbwheel actuated vascular intervention device delivery system

ABSTRACT

A vascular intervention device delivery system, such as for implanting a stent, includes a thumbwheel rotatably mounted in a handle. A catheter has a proximal end attached to the handle, and a distal carrier segment for mounting a vascular intervention device thereon. A retractable sheath is movable from a first position covering the distal carrier segment to a second position retracted proximally uncovering the distal carrier segment. A pull extends between the thumbwheel and the retractable sheath. A latch is positioned in the handle and moveable from a locked position at which the latch engages the radially outward thumb surface, and an unlocked position at which the latch is out of contact with the thumbwheel. A pusher, which is partially positioned outside of the handle, is operable to move the latch from the locked position to the unlocked position. The retractable sheath moves responsive to rotation of the thumbwheel.

TECHNICAL FIELD

The present disclosure relates generally to vascular intervention devicedelivery systems, and more particularly to features that lock thethumbwheel against rotation while the distal end of the device ismaneuvered to a delivery site.

BACKGROUND

Self expanding stents and similar vascular intervention devices areoften delivered and deployed using so called pin and pull systems.Typically, the stent is compressed between a retractable outer sheathand an inner catheter. To deploy the stent, the user has to pull theouter sheath to uncover the stent using one hand while resisting theforce with the other hand on the inner catheter to maintain the positionof the stent during deployment. In pin and pull systems, the user canhave difficultly maintaining the inner catheter at a fixed positionwhile simultaneously moving the outer sheath. In very difficult stentdeployments, which require a large amount of force by the user, thissimultaneous push and pull may lead to inaccurate stent positioning,shortening or lengthening of the stent, or possibly even damage to thestent or target vessel. Another disadvantage of pin and pull systems isthat there can be a lack of control on the deployment because the forceto deploy the stent decreases as more of the stent is deployed. If theuser maintains the same high force during deployment, the stent may bedeployed too fast for the user to control. Another potential problemrelates to building up tension in the outer sheath prior to movementsthereof during the deployment process. If the user pauses during thedeployment and releases this built up tension, deployment errors canoccur when the user resumes tension to again move the outer sheath tothe deployment position fully uncovering the self explaining stent.Another concern for stent deployment systems is ensuring that frictionencountered as the distal end is maneuvered to a delivery site does notcause the stent to be prematurely uncovered.

The present disclosure is directed toward one or more of the problemsset forth above.

SUMMARY OF THE DISCLOSURE

In one aspect, a vascular intervention device delivery system includes athumbwheel with a radially outward thumb surface rotatably mounted in ahandle. A catheter has a proximal end attached to the handle, and adistal carrier segment for mounting a vascular intervention devicethereon. A retractable sheath is movable from a first position coveringthe distal carrier segment to a second position retracted proximallyuncovering the distal carrier segment. A pull extends between thethumbwheel and the retractable sheath. A lock is movable between alocked position and an unlocked position. The lock includes a latchpositioned in the handle and movable along a line between the lockedposition at which the latch engages the radially outward thumb surface,and the unlocked position at which the latch is out of contact with theradially outward thumb surface.

In another aspect, a method of operating the vascular interventiondevice delivery system includes maneuvering the distal carrier segmenttoward a delivery site while the latch is in the locked position. Thelatch is moved from the locked position to the unlocked position afterthe distal carrier segment arrives at the delivery site. The distalcarrier segment is uncovered responsive to rotating the thumbwheel in afirst direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective schematic view of a vascular intervention devicedelivery system according to the present disclosure;

FIG. 2 is an enlarged view of the distal segment of the delivery systemshown outlined with a dashed line in FIG. 1;

FIG. 3 is a view similar to FIG. 2 about half way through a deploymentof a self expanding stent;

FIG. 4 is a perspective view of an assembly plate for the handle shownin FIG. 1;

FIG. 5 is a partial sectioned view showing the ratchet according to thepresent disclosure;

FIG. 6 is a sectioned side view through the thumbwheel of FIGS. 1 and 5;

FIG. 7 is a sectioned side view of a handle portion of a vascularintervention device delivery system according to another aspect of thepresent disclosure;

FIG. 8 is a top view of the inner workings of the vascular interventiondevice delivery system of FIG. 7, minus the handle;

FIG. 9 is a side view of a ratchet pawl for the vascular interventiondevice delivery system of FIG. 7;

FIG. 10 is a sectioned side view similar to that of FIG. 7 except afterthe lock has been moved to the unlocked position;

FIG. 11 is a perspective view of the latch portion of the lock accordingto another aspect of the present disclosure; and

FIG. 12 is a perspective view of the pusher for the embodiment of FIG.7.

DETAILED DESCRIPTION

Referring to FIGS. 1-3, a vascular intervention device delivery system10 is shown before and during delivery of a self expanding stent 45 intothe vessel 50 of a patient. Delivery system 10 includes a handle 11 thatmay be gripped in one hand by a user during a delivery procedure. Handle11 may, for instance, be manufactured from a suitable molded plastic,such as in two longitudinal halves that are joined in any suitablemanner to form the complete handle 11. A thumbwheel 15 is rotatablymounted in the handle 11 and has a radially outward thumb surface 16 anda spool 17. A catheter 30 has a proximal end 31 attached to handle 11,and a distal carrier segment 32 for mounting a vascular interventiondevice, such as a self expanding stent 45, thereon. Proximal end 31 maytake the form a Luer lock fitting to receive a wire guide, or so thattreatment fluids or the like may be injected through catheter 30 in amanner well known in the art. A retractable sheath 37 is movable withrespect to catheter 30 from a first position covering the distal carriersegment 32 to a second position indicated by the dashed line in FIG. 3at which the retractable sheath 37 has been retracted proximally touncover the distal carrier segment 32. FIG. 3 shows the retractablesheath 37 about half way between the first position and the secondposition at a delivery site 51 in a blood vessel 50.

A pull 38 extends between the spool 17 of thumbwheel 15 and theretractable sheath 37. Pull 38, which preferably is less elastic thanthe retractable sheath 37, may be attached to retractable sheath 37 atan attachment 39 in any manner known in the art, such as by welding pull38 to a metallic reinforcement of retractable sheath 37. In mostversions of the vascular intervention device delivery system 10 of thepresent disclosure, pull 38 will be longer than retractable sheath 37.Nevertheless, retractable sheath 37 could be longer than pull 38 withoutdeparting from the present disclosure. Pull 38 may comprise a metallicwire or thin band of metal.

A wire retention/stability sheath 42 surrounds a majority of the lengthof pull 38, and serves to keep pull 38 in close proximity to the outersurface of catheter 30 over much of the length of delivery system 10.Wire retention/stability sheath 42 may be unattached to catheter 30,pull 38 or retractable sheath 37, but may be attached to move with pull38 and/or retractable sheath 37. On the other hand, wireretention/stability sheath 42 may be attached to catheter 30 at one ormore locations so that pull 38 and retractable sheath 37 also move withrespect to wire retention/stability sheath 42 during the deliveryprocess. Wire retention/stability sheath 42 may terminate and beattached at its proximal end at a fixation point within handle 11.

When in its pre-deployment configuration, as shown in FIGS. 1 and 2, avascular intervention device, such as a self expanding stent 45, isdisposed between an outer surface of the distal carrier segment 32 ofcatheter 30, and an inner surface of the retractable sheath 37. During atypical procedure, the distal carrier segment 32 is positioned at adelivery site 51 within a vessel 50 of a patient. After achieving properpositioning, the user then grips handle 11 and begins to rotatethumbwheel 15 so that pull 38 is wound onto spool 17. As this occurs,pull 38 and retractable sheath 37 move proximally with respect tocatheter 30 to allow the self expanding stent 45 to expand away fromcarrier segment 32 and into contact with the inner wall of vessel 50 ina manner well known in the art. During this process, catheter 30 isplaced in compression while both pull 38 and retractable sheath 37 arein tension. According to the present disclosure, handle 11 andthumbwheel 15 include a structure that allows thumbwheel 16 to rotate towind pull 38 onto spool 17, but prevent rotation in an oppositedirection. This aspect of the disclosure allows the user to stop thedeployment procedure while retaining the stored elastic energy in pull38 and retractable sheath 37.

Referring now in addition to FIGS. 4-6, a ratchet 20 provides thestructure that prevents thumbwheel 16 from rotating in a forwarddirection. In particular, handle 11 may be formed to include, or haveattached to an inner surface, an assembly plate 12 that defines a hub 13that receives an axle 36 upon which thumbwheel 16 is rotatably mountedto rotate about axis 14 in a reverse direction permitted by ratchet 20.Thumbwheel 15 includes a radially inward ratchet surface 31 of ratchet20. A ratchet pawl 22 of ratchet 20 is mounted in the handle 11, and hasa catch 23 in contact with ratchet surface 21 of thumbwheel 15. Ratchet20 holds thumbwheel 15 against rotation in a forward direction, but theretractable sheath 37 moves responsive to rotation of the thumbwheel 15in a reverse direction.

In the illustrated embodiment, catch 23 takes the form of a deformedrectangular shaped band of spring steel 24 that is received in anS-shaped groove 19 defined by assembly plate 12 and oriented parallel toaxis 14. The ratchet surface 21 of thumbwheel 15 may define a pluralityof stops 25 in each of four 90° rotation angles. In the specificembodiment shown, ratchet surface 21 defines at least fifty stops 25 perrevolution of thumbwheel 15 in order to provide the user with precisetactile control over the delivery procedure. The deformed band of springsteel 24 may have a width that contacts the ratchet surface 21 acrossthe width 26. In addition, although not necessary, the deformed band ofspring steel 24 may have a length 27 that is greater than radius 18 ofthumbwheel 15. An imaginary line 40 that extends parallel from an end 28of catch 23 to the axis 14 may be configured to be orthogonal to pull 38where pull 38 contacts spool 37, as best shown in FIG. 5.

Referring now to FIGS. 7-12, a vascular intervention device deliverysystem 60 according to another aspect includes a ratchet 70 and a handle61 with a structure that differs from that shown in relation to FIGS.4-6. However, where similar numbers are used, those features correspondto similar features shown in FIGS. 1-3. Vascular intervention devicedelivery system 60 differs from the system 10 described earlier by theshape and structure of the ratchet pawl 72 and by the inclusion of alock 80. Like the earlier version, ratchet 70 provides a structure thatprevents thumbwheel 66 from rotating in a forward direction.

Handle 61 may be formed from a suitable plastic to include a key shapedhub 62 that is received in a matching key shaped opening 74 defined byratchet pawl 72. This configuration permits assembly of ratchet pawl 72to key shaped hub 62 in a plurality of different but equivalent angularorientations. Key shaped hub 72 may define a central opening thatreceives an axle 63 to define an axis 64 about which thumbwheel 65rotates. Thumbwheel 65 includes a radially outward thumb surface 66 anda radially inward ratchet surface 71. Thumbwheel 65 may also include aspool 67 upon which the pull 38 is wound when the device delivery system60 is operated. In this version, the wire retention/stability sheath 42terminates at a junction box 43 (not shown in FIG. 7 for the sake ofclarity) positioned within handle 61. As in the previous version, thepull 38 is positioned within the wire retention/stability sheath 42 andemerges from the junction box 43 to wrap around an idler wheel 44 andreturn in the reverse direction for being wound onto spool 67 as bestshown in FIGS. 7 and 8. As in the previous embodiment, ratchet 70prevents thumbwheel 65 from rotating in a forward direction, but theretractable sheath 37 (FIGS. 1-3) moves responsive to rotation ofthumbwheel 65 in a reverse direction.

In this embodiment, catch 73 takes the form of spiral arms 79 that areattached to a central body 76 by living hinges 77. Unlike the ratchetpawl 22 shown in the embodiment in FIGS. 4-6, ratchet pawl 72 may mostconveniently be formed of a suitable plastic material. When thumbwheel65 is rotated in a reverse direction, each of the three catches 73 willclick and be received into respective stops 75 that define ratchetsurface 71. In this embodiment, ratchet catches 73 are equallydistributed 120° apart around the axis 64 defined by axle 63. Thus, thethree catches 73 will simultaneously contact the ratchet surface 71 atthree different locations located 120° apart about axis 64. Thoseskilled in the art will appreciate that a ratchet pawl 72 having two,four or more catches 73 would also fall within the intended scope ofthis disclosure.

As best shown in FIGS. 7 and 9, the ratchet pawl 72 includes curved arms78 that are distributed to provide a circular guide for the thumbwheelas the ratchet teeth rotate around the fixed ratchet. Thus, in someembodiments, the use of curved arms 78 could permit omission of axle 63as shown, since the thumbwheel would rotate about axis 64 with thecurved arms 78 contacting ratchet surface 71, even without the inclusionof axle 63. It is also worth noting that this embodiment differs fromthe earlier embodiment in that both the ratchet pawl 72 and the ratchetsurface 71 of thumbwheel 65 may be made out of plastic, as opposed to ametal ratchet pawl 22 acting on a plastic ratchet surface 21 as in theearlier embodiment. By making both the pawl and the ratchet surface fromthe same material, the potential creation of the debris caused by theinteraction of metal with plastic can be avoided.

In addition to ratchet 70, vascular intervention device delivery system60 includes a lock 80 that allows thumbwheel 65 to be disabled duringshipment and during positioning of the distal carrier segment 32 (FIGS.1-3) at a treatment location within a patient. The lock 80 is movablebetween a locked position, as shown in FIG. 7, and an unlocked positionas shown in FIG. 10. The lock 80 includes a latch 81 positioned inhandle 61 and movable along a line 82 between the locked position atwhich the latch 81 engages the radially outward thumb surface 66 ofthumbwheel 65, and the unlocked position at which the latch 81 is out ofcontact with the radially outward thumb surface 66. Lock 80 alsoincludes a pusher 85 that is at least partially positioned outside ofhandle 61, but on an opposite side of handle 61 from the exposed portionof thumbwheel 65. The pusher may include a wedge 86 that engages a post83 of latch 81. Post 83 may be oriented perpendicular to the line 82 ofaction of latch 81. Vascular intervention device delivery system may beenabled by depressing pusher 85 along line 87 to move latch 81 out ofcontact with radially outward thumb surface 66 of thumbwheel 65.

Preferably, during shipping and while the distal carrier segment 32 isbeing maneuvered to a delivery site 51, the latch 81 is maintained inthe locked position by engaging a latch hook 88 with a catch surface 68of handle 61. Latch hook 88 may be connected to a latch body 89 by aliving hinge 90. Latch 81 may be formed from a single piece of plasticinto the form shown in FIG. 11. Likewise, catch surface 68 may be formedas part of handle 61. Nevertheless, these features may be separatecomponents without departing from the present disclosure. When the latchhook 88 is engaged with the catch surface 68 as shown in FIG. 7, thelatch 81 is maintained in the locked position; however, the latch 81 maybe moved to the unlocked position as shown in FIG. 10 when latch hook 88is dis-engaged from catch surface 68. Thus, latch 81 is blocked frommovement toward the unlocked position when the latch hook 88 is engagedwith catch surface 68. Although latch 81 is shown as moving along aline, a rotational latch could also fall within the intended scope ofthe present disclosure.

Disengagement of latch hook 88 from catch surface 68 may be accomplishedby moving pusher 85 from its first position as shown in FIG. 7 to asecond position as shown in FIG. 10. Pusher 85 may include a liftsurface 91 that lifts latch hook 88 out of engagement with catch surface68 against the action of living hinge 90 when the pusher 85 is movedfrom the first position toward the second position. Preferably, movementof pusher 85 into handle 61 from its first position toward its secondposition sequentially disengages latch hook 88 from latch catch surface68 before wedge 86 of pusher 85 contacts post 83 to move latch 81 fromits locked position as shown in FIG. 7 to its unlocked position as shownin FIG. 10. This action of pusher 85 and latch 81 may be designed to bea one time irreversible movement by forming pusher 85 to include apusher hook 93 attached to pusher body 92 by a living hinge 94. As withlatch 81, pusher 85, pusher hook 93 and living hinge 94 may be formedfrom a single piece of plastic, but could be separate attached featureswithout departing from the present disclosure. When pusher 85 is pushedall the way into handle 61 to its second position as shown in FIG. 10,pusher hook 93 may engage a pusher catch surface 69, which blocks pusher85 from movement backwards from its second position toward its firstposition. When pusher 85 is in its first position as shown in FIG. 7,pusher hook 93 is out of contact with pusher catch surface 69. Whenpusher is in its second position, pusher 85 blocks movement of latch 81from the unlocked position shown in FIG. 10 back toward the lockedposition as shown in FIG. 7. This feature may help to prevent accidentalengagement of latch 81 with thumbwheel 65 that might otherwise occurafter the distal carrier segment has arrived at the delivery site 51.For instance, it may be undesirable for the latch to move back towardthe locked position during a pause in the deployment of stent 45 atdelivery site 51. Pusher 85 may also include a flange 95 that not onlyhelps to prevent pusher 85 from escaping from handle 61, but also servesto limit access to, and viewing of, the inner workings of vascularintervention device delivery system 60.

INDUSTRIAL APPLICABILITY

The present disclosure is generally applicable to vascular interventiondevice delivery systems, and more particularly to a delivery system fordelivery of self expanding stents and other vascular interventiondevices with self expanding action. The present disclosure findsspecific applicability to delivery of relatively long vascularintervention devices that produce substantial friction on the innersurface of retractable sheath 37, and thus require higher forces onretractable sheath 37 and pull 38 in order to successfully deliver thevascular intervention device to an intended treatment site.

The vascular intervention device delivery system 10, 60 will typicallybe packaged in a conventional sterile packaging in a known manner forshipment. After a wire guide (not shown) has been positioned in apatient's body across a treatment location, the catheter 30 may be slidover the wire guide and maneuvered to position the distal carriersegment 32 and the attached self expanding stent 45 at the delivery site51 within the vessel 50 of the patient. Thereafter, the wire guide maybe withdrawn or left in place. During this portion of the procedure, thethumbwheel 65 of the vascular intervention device delivery system 60 maybe disabled by maintaining the lock 80 in its locked position as shownin FIG. 7. This may be accomplished by engagement of latch hook 88 withlatch catch surface 68. After the distal carrier segment 32 is properlypositioned and it is now time to deploy the self expanding stent 45, theuser may depress pusher 85 into handle 61 to disengage lock 80 and movelatch 81 out of contact with the radially outward thumb surface 66 ofthumbwheel 65.

When pusher 85 is pushed into handle 61 from its first position as shownin FIG. 7 to its second position as shown in FIG. 10, the pusher maysequentially disengage latch hook 88 from latch catch surface 68 beforewedge 86 engages post 83 to move latch 81 toward its unlocked position.In order to inhibit reverse action, the pusher hook 93 may engage apusher catch surface 69 formed in handle 61 after pusher 85 arrives atits second position as shown in FIG. 10. When in its second position,the pusher 85 blocks movement of latch 81 from the unlocked positiontoward the locked position.

A method of operating vascular intervention device delivery system 10,60 includes rotating the thumbwheel 15, 65 in a reverse direction towind pull 38 onto spool 17, 67 to build up tension in the retractablesheath 37 and pull 38 without moving the retractable sheath 37 relativeto the distal carrier segment 32 of catheter 30. The “reverse direction”is clockwise for the embodiment of FIG. 1 and counterclockwise for theembodiment of FIG. 7. Next, a portion, which is less than all, of thedistal carrier segment 32 is uncovered by continuing to rotate thethumbwheel 15, 65 in the reverse direction. At some point during thedelivery procedure, the user may then pause rotation of the thumbwheel15, 65 in the reverse direction. For instance, the user may pause inorder to confirm that the vascular intervention device, such as a selfexpanding stent 45, is being delivered to the desired location in thevessel 50 of the patient. While the rotation of the thumbwheel 15, 65 ispaused, tension in the pull 38 and the retractable sheath 37 ismaintained by holding the ratchet 20, 70 and preventing rotation of thethumbwheel 15, 65 in the forward direction. Ratchet 20, 70 may beconsidered to be in a hold configuration when catches 23, 73 arereceived in one of the stops 25, 75 of the ratchet surface 21, 71. Aremaining portion of the distal carrier segment 32 is then uncovered tofacilitate complete deployment of the self expanding stent 45 byresuming rotation of the thumbwheel 15, 65 in the reverse directionuntil retractable sheath 37 arrives at its second position fullyuncovering distal carrier segment 32.

An important aspect of the ratchet operated vascular intervention devicedelivery system 10, 60 of the present disclosure is to allow forrotation of thumbwheel 15, 65 in one direction only. This means that thepull 38 and hence the retractable sheath 37 can only be pulledproximally. If the thumbwheel 15, 65 were able to rotate in bothdirections, it could cause the pull 38 to slack and possibly jump out ofthe collection diameter of the spool 17, 67 on thumbwheel 15, 65. Also,by keeping the rotation of thumbwheel 15, 65 to one direction only,ratchet 20, 70 allows all of the energy already placed in the system 10,60 by the user to be maintained. For example, if the user was topartially deploy a self expanding stent 45 that had a deployment forceof 30N they will have to put effort into getting the stent to partiallydeploy. This effort could have caused the sheath 37 to stretch slightlyand also the inner catheter 30 to compress slightly. If this energy werelost when the thumbwheel 15, 65 were released, it would mean that whenthe deployment was resumed from that point, the user would have torotate the thumbwheel 15, 65 an amount in order to reestablish tensionin the system 10, 60 again before the self expanding stent 45 wouldcontinue to deploy. This may be especially important in the case ofdeploying longer stents that require higher forces.

It should be understood that the above description is intended forillustrative purposes only, and is not intended to limit the scope ofthe present disclosure in any way. Thus, those skilled in the art willappreciate that other aspects of the disclosure can be obtained from astudy of the drawings, the disclosure and the appended claims.

What is claimed is:
 1. A vascular intervention device delivery systemcomprising: a handle; a thumbwheel rotatably mounted in the handle andhaving a radially outward thumb surface; a catheter with a proximal endattached to the handle, and a distal carrier segment for mounting avascular intervention device thereon; a retractable sheath movable froma first position covering the distal carrier segment to a secondposition retracted proximally uncovering the distal carrier segment; alatch positioned in the handle and movable between the locked positionat which the latch contacts and engages the radially outward thumbsurface, and the unlocked position at which the latch is out of contactwith the radially outward thumb surface; and the retractable sheathmoving toward the second position responsive to rotation of thethumbwheel in a first direction.
 2. The vascular intervention devicedelivery system of claim 1 wherein the latch includes a hook connectedto a latch body by a living hinge; the handle includes a catch surfaceengaged with the hook when the latch is in the locked position, and thehook being disengaged from the catch surface when the latch is in theunlocked position; and wherein the latch being blocked from movementtoward the unlocked position when the hook is engaged with the catchsurface.
 3. The vascular intervention device delivery system of claim 2including a pusher at least partially positioned outside the handle andbeing operably coupled to move the latch from the locked position to theunlocked position responsive to the pusher moving into the handle. 4.The vascular intervention device delivery system of claim 3 wherein thepusher is movable from a first position to a second position; and thepusher has a lift surface that lifts the hook out of engagement with thecatch surface against an action of the living hinge when the pusher ismoved from the first position toward the second position.
 5. Thevascular intervention device delivery system of claim 4 wherein thepusher is movable from a first position to a second position; and thepusher includes a wedge that engages the latch when the pusher is movedfrom the first position toward the second position.
 6. The vascularintervention device delivery system of claim 3 wherein the latch isblocked by the pusher from movement to the locked position when thepusher is at the second position.
 7. The vascular intervention devicedelivery system of claim 6 wherein the latch hook is disengaged from thelatch catch surface, and the wedge engages the post, sequentially, whenthe pusher is moved from the first position to the second position.
 8. Avascular intervention device delivery system comprising: a handle; athumbwheel rotatably mounted in the handle and having a radially outwardthumb surface; a catheter with a proximal end attached to the handle,and a distal carrier segment for mounting a vascular intervention devicethereon; a retractable sheath movable from a first position covering thedistal carrier segment to a second position retracted proximallyuncovering the distal carrier segment; a pusher at least partiallypositioned outside the handle and being movable from a first position toa second position, and the pusher moving into the handle responsive tomovement from the first position toward the second position; wherein thethumbwheel is enabled to rotate responsive to movement of the pusherfrom the first position to the second position; and the retractablesheath moving toward the second position responsive to rotation of thethumbwheel in a first direction when the thumbwheel is enabled torotate.
 9. The vascular intervention device delivery system of claim 8including a latch positioned entirely in the handle and movable betweena locked position at which the latch contacts and engages thethumbwheel, and an unlocked position at which the latch is out ofcontact with the thumbwheel; and the pusher being operably coupled tomove the latch from the locked position to the unlocked positionresponsive to the pusher moving from the first position toward thesecond position.
 10. The vascular intervention device delivery system ofclaim 9 wherein the latch is blocked by the pusher from movement to thelocked position when the pusher is at the second position.
 11. Thevascular intervention device delivery system of claim 9 wherein thelatch includes a hook connected to a latch body by a living hinge; thehandle includes a catch surface engaged with the hook when the latch isin the locked position, and the hook being disengaged from the catchsurface when the latch is in the unlocked position; and wherein thelatch being blocked from movement toward the unlocked position when thehook is engaged with the catch surface.
 12. The vascular interventiondevice delivery system of claim 11 wherein the pusher has a lift surfacethat lifts the hook out of engagement with the catch surface against anaction of the living hinge when the pusher is moved from the firstposition toward the second position.
 13. The vascular interventiondevice delivery system of claim 12 wherein the pusher includes a wedgethat engages the latch when the pusher is moved from the first positiontoward the second position.